Urea fertilizer compositions comprising rice hulls and methods of use

ABSTRACT

Compositions comprising urea containing fertilizer (e.g., urea fertilizers or urea formaldehyde reaction product fertilizers such as urea-formaldehyde fertilizer or methylene urea fertilizers) and rice hulls, as well as methods of making and using such compositions are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/073,181 filed Mar. 17, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/962,720, filed Dec. 8, 2015, which claims thebenefit of U.S. Provisional Patent Application No. 62/089,443, filedDec. 9, 2014, the disclosures of which are incorporated by referenceherein in their entireties.

FIELD OF THE INVENTION

Compositions comprising urea fertilizer and rice hulls, as well asmethods of making and using such compositions are provided.

BACKGROUND OF THE INVENTION

Urea containing fertilizer compositions (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) have been known and used formany years. Urea containing fertilizers (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) provide a high level ofnitrogen availability, which is necessary to maintain growth and colorof lawn turf. Examples of urea containing fertilizers (e.g., ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) aredisclosed in U.S. Pat. Nos. 3,076,700; 3,231,363; 3,223,518; 4,025,329;5,102,440; and 6,039,781, each of which are hereby incorporated byreference in their entireties.

Urea containing fertilizers (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) in general, including solid or granulatedurea containing fertilizers, have a tendency to cake or clump over time,such as during storage, causing problems in spreading and/ordisseminating the resulting caked or clumped fertilizer products. SeeU.S. Pat. No. 7,776,125, hereby incorporated by reference in itsentirety. Urea containing fertilizers, because they are hygroscopic,develop crystal bridges as they age under typical storage conditions.These crystal bridges result in hard caking and lump formation, thusmaking the fertilizer more difficult to use effectively. Urea crystalgrowth is a major component of urea containing fertilizers and one ofthe important driving forces in the caking process. Urea crystal growthalso can develop so extensively that the entire particle surface iscovered with urea crystals. When this occurs on fertilizer productscontaining surface applied active ingredients, overall active ingredientperformance can be negatively affected. The net result is lower activeingredient control of weeds or other targeted pests.

Anti-caking agents and crystal modifiers are typically applied directlyto the surface urea-containing fertilizers. For example, knownanti-caking agents normally have been applied to the surface of thefertilizer particles, and due to inefficient coating techniques, haveresulted in only partially coated granules, providing less thaneffective reduction in caking of the granules. In addition, over time,such surface applied coatings may break away from the granules, and thusthe treatment slowly loses effectiveness. WO 2012/129847; U.S. Pat. Nos.3,041,159; 3,325,276; 3,558,299; 3,852,055; 7,108,732; and 8,492,444,each of which are hereby incorporated by reference in their entireties.These materials have somewhat limited performance because of inefficientcoating techniques, resulting in partially coated granules. In addition,over time the surface applied coating may break away from or strike intothe granule and thus slowly lose effectiveness.

Solid anti-caking agents found in the art, such as vermiculite, areeffective if larger quantities are utilized and the vermiculite is usedas a parting agent. But if the vermiculite is granulated and coveredwith urea containing fertilizer resin, the anti-caking benefits areeliminated.

In sum, anti-caking agents and crystal modifiers known in the art havenot satisfactorily solved the caking/clumping problems in ureacontaining fertilizers (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers).

SUMMARY OF VARIOUS EMBODIMENTS OF THE INVENTION

In one aspect, the invention relates to compositions comprising ricehulls and a urea containing fertilizer. These compositions show, amongother things, less crystal formation and less clumping when stored overtime, and reduced loss of usable product (e.g., herbicide), as comparedto a urea containing fertilizer not comprising rice hulls.

In one embodiment, a fertilizer composition may comprise granulescomprising rice hulls and a urea containing fertilizer. In anembodiment, the rice hulls may be comminuted in size. In an embodiment,the rice hulls may be ground. In an embodiment, the rice hulls may beabout 20-70 SGN. In an embodiment, the rice hulls may be about 20-70SGN, 30-60 SGN, 45-55 SGN, 30-50 SGN, 40-60 SGN, 45-50 SGN, or 50-55 SGNin size. In an embodiment, the rice hulls may be about 40-60 SGN. In anembodiment, the rice hulls may be about 20, 21, 22, 23, 24, 25, 26, 27,28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45,46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,64, 65, 66, 67, 68, 69, or 70 SGN in size. In an embodiment, the ricehulls may be about 50 SGN.

In one embodiment, when the fertilizer composition described herein isstored over a period of time between 1 and 8 months, for example 1, 2,3, 4, 5, 6, 7, or 8 months, it may have a reduced crystal aspect ratiocompared to a fertilizer composition not having rice hulls stored forthe same period of time. In another embodiment, the crystal aspect ratioof the fertilizer composition described herein may be reduced to a levelin a range from about 30:1 to about 4:1, for example, 30:1, 27:1, 25:1,23:1, 20:1, 19:1, 17:1, 16:1, 15:1, 13:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1,or 4:1. In another embodiment, the months of storage may be from between2 and 8 months, for example 2, 3, 4, 5, 6, 7, or 8 months.

In one embodiment, the rice hulls may be about 1-50% by weight of thegranule. In an embodiment, the rice hulls may be about 5-50%, 10-40%,20-30%, 15-30%, 20-35%, 15-40%, 15-30%, 10-20%, 10-25%, 15-25%, 15-35%,25-50%, or 15-50% by weight of the granule. In an embodiment, the ricehulls may be about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50% by weight ofthe granule. In an embodiment, the rice hulls may be about 10-25% byweight of the granule. In an embodiment, the rice hulls may be about 20%by weight of the granules.

In any of the embodiments, the urea-based fertilizer may be a ureacontaining fertilizer resin (e.g., a resin of urea fertilizer or ureaformaldehyde reaction product fertilizer such as urea-formaldehydefertilizer or methylene urea fertilizers). In an embodiment, the ureacontaining fertilizer resin (e.g., a resin of urea fertilizer or ureaformaldehyde reaction product fertilizer such as urea-formaldehydefertilizer or methylene urea fertilizers) may have a urea toformaldehyde ratio of about 1.5:1 to about 8:1. In an embodiment, theratio may be about 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, or 8:1. In anembodiment, the ratio may be about 4:1.

In one embodiment, the average crystal area of urea crystals formed inthe fertilizer composition described herein after between 2 and 8months, for example 2, 3, 4, 5, 6, 7, or 8 months, is less than 60 μm².In an embodiment, the average crystal area of urea crystals formed inthe fertilizer composition described herein after between 2 and 8months, for example 2, 3, 4, 5, 6, 7, or 8 months, may be less than 30,less than 35, less than 40, less than 45, less than 50, less than 55, orless than 60 μm².

In one embodiment, the fertilizer composition described herein maycomprise less than 1, less than 2, less than 3, less than 4, less than5, less than 6, less than 7, less than 8, less than 9, less than 10,less than 11, less than 12, less than 13, less than 14, less than 15,less than 16, less than 17, less than 18, less than 19, or less than 20%water by weight of the granule. In an embodiment, the composition maycomprise less than 5% water by weight of the granule.

In other embodiments, the granules described herein may be about 1-5 mmin size. In other embodiment, the granules may be from about 0.5 toabout 5 mm in size, for example 0.5, 0.75, 1, 2, 3, 4, or 5 mm in size.In other embodiment, the granules may be about 1-3, 1-5, 2-3, 0.75-3,0.5-1, or 1-2 mm in size.

In the above embodiments, the composition may comprise granulescomprising ground rice hulls coated with a urea containing fertilizerresin (e.g., a resin of urea fertilizer or urea formaldehyde reactionproduct fertilizer such as urea-formaldehyde fertilizer or methyleneurea fertilizers), potassium sulfate, ammonium sulfate,3,6-Dichloro-2-methoxybenzoic acid (dicamba), 2,4-dichlorophenoxy aceticacid (2,4-D), and methyl chlorophenoxy propionic acid (MCPP-P). In otherembodiments, the granule may comprise 40-60% by weight urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers). In other embodiments, the granule may comprise about 58%by weight urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers). In other embodiments, thegranule may comprise 10-25% by weight ground rice hulls. In otherembodiments, the granule may comprise 20% by weight ground rice hulls.In other embodiments, the granule may comprise about 5-10% by weightpotassium sulfate. In other embodiments, the granule may comprise about6.5% by weight potassium sulfate. In other embodiments, the granule maycomprise about 10-20% by weight ammonium sulfate. In other embodiments,the granule may comprise about 13.5% by weight ammonium sulfate. Inother embodiments, the granule may comprise 0.5-4% by weight2,4-dichlorophenoxy acetic acid (2,4-D). In other embodiments, thegranule may comprise about 1.25% 2,4-dichlorophenoxy acetic acid(2,4-D). In other embodiments, the granule may comprise about 0.5-1.5%by weight methyl chlorophenoxy propionic acid (MCPP-P). In otherembodiments, the granule may comprise about 0.7% methyl chlorophenoxypropionic acid (MCPP-P). In one embodiment, the granule may compriseabout 0.04-0.2% by weight 3,6-Dichloro-2-methoxybenzoic acid (dicamba).

In the above embodiments, the fertilizer composition described hereinmay further comprise fertilizer components. In the above embodiments,the granules described herein may further comprise fertilizercomponents. In other embodiments, the fertilizer components may bepotassium sulfate, micro elements, mono-ammonium phosphate, potassiumchloride, or mixtures thereof. In other embodiments, the fertilizercomponent may be calcium nitrate, ammonium sulfate, coated urea (such aspolymer coated urea or sulfur-coated urea), isobutylidene dirurea,ammonium nitrate, ureaform, methylene urea, urea, anhydrous ammonia,ammonium polyphosphate, monoammonium phosphate, diammonium phosphate,potassium nitrate, or mixtures thereof.

In the above embodiments, the composition may further compriseherbicides, micronutrients, biostimulants, macronutrients, inert solidcarriers, or mixtures thereof.

In the above embodiments, the granule further may comprise herbicides,micronutrients, biostimulants, macronutrients, inert solid carriers, ormixtures thereof.

In the above embodiments, the composition described herein may be acontrolled release fertilizer.

In the above embodiments, the granule described herein may be acontrolled release fertilizer.

In the above embodiments, the composition may comprise less than 1, lessthan 2, less than 3, less than 4, less than 5, less than 6, less than 7,less than 8, less than 9, less than 10, less than 11, less than 12, lessthan 13, less than 14, less than 15, less than 16, less than 17, lessthan 18, less than 19, or less than 20% water by weight of thecomposition. In other embodiments, the composition may comprise lessthan 5% water by weight of the composition.

In the above embodiments, the granule described herein may comprise lessthan 1, less than 2, less than 3, less than 4, less than 5, less than 6,less than 7, less than 8, less than 9, less than 10, less than 11, lessthan 12, less than 13, less than 14, less than 15, less than 16, lessthan 17, less than 18, less than 19, or less than 20% water by weight ofthe composition. In other embodiments, the granule may comprise lessthan 5% water by weight of the composition.

In the above embodiments, the composition described herein may produceless of an odor than a fertilizer with a similar amount of urea. Inother embodiments, the composition may have an average odorconcentration of less than 550 o.u./m³.

In the above embodiments, the granules described herein may produce lessof an odor than a fertilizer with a similar amount of urea. In otherembodiments, the granules may have an average odor concentration of lessthan 550 o.u./m³.

In the above embodiments, a soil amendment may comprise the fertilizercomposition described herein.

In the above embodiments, a soil additive may comprise the fertilizercomposition described herein.

In the above embodiments, a method of fertilizing a plant may compriseadding the fertilizer composition described herein to a plant.

In the above embodiments, a method of feeding a plant may compriseadding the fertilizer composition described herein to a plant.

In the above embodiments, a method of promoting plant growth maycomprise administering the fertilizer composition described herein to aplant life. In other embodiments, the plant life may be a plant, plantcutting, or seed. In other embodiments, the plant may be young plant,transplant, or seedling.

In the above embodiments, a method of making a soil may compriseadmixing the fertilizer composition described herein with a soil.

In the above embodiments, a soil may comprise the fertilizer compositiondescribed herein.

In the above embodiments, a method of amending a soil may compriseadmixing the fertilizer composition described herein with a soil.

In the above embodiments, a method of making a fertilizer compositionwith fewer urea crystals as compared to a fertilizer not comprising ricehulls may comprise spraying urea containing fertilizer resin (e.g., aresin of urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) onto rice hulls and forming a granule. In otherembodiments, the fertilizer composition has about 10-30% fewer ureacrystals than a fertilizer not comprising rice hulls.

In the above embodiments, a method of making the fertilizer compositionmay comprise spraying molten urea containing fertilizer resin (e.g., aresin of urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) onto rice hulls and forming a granule. In otherembodiments, the rice may be hulled by dry milling or parboiling. Inother embodiments, the rice may be hulled by dry milling. In otherembodiments, the method may further comprise comminuting the rice hullsin size. In other embodiments, the method may further comprise addingfertilizer nutrients. In other embodiments, the fertilizer nutrients maybe potassium sulfate, micro elements, mono-ammonium phosphate, potassiumchloride, or mixtures thereof. In other embodiments, the fertilizer isgranular. In other embodiments, the granulation may be done in arotating drum, fluidized bed, pan, pellet mill, or a combinationthereof. In other embodiments, the granulation may be performed at atemperature from about 130-160° F. In other embodiments, the molten ureacontaining fertilizer resin (e.g., a resin of urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) may be at a temperature ofabout 270-275° F.

In the above embodiments, a method for reducing the crystal aspect ratioof crystals formed in a fertilizer may comprise adding rice hulls in anamount sufficient to lower the crystal aspect ratios of the crystalsformed in the fertilizer after storage. In other embodiments, thecrystal aspect ratios of the crystals formed in the urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) may be reduced to a level in a range from about 30:1 toabout 4:1, for example, 30:1, 27:1, 25:1, 23:1, 20:1, 19:1, 17:1, 16:1,15:1, 13:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, or 4:1. In anotherembodiment, the crystal aspect ratios of the crystals formed in the ureacontaining fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) may be reduced after from about 1 to about 8months of storage, for example 1, 2, 3, 4, 5, 6, 7, or 8 months ascompared a fertilizer not comprising rice hulls.

In the above embodiments, a method for reducing the number of ureacrystals formed in a fertilizer may comprise adding rice hulls in anamount sufficient to lower the crystal aspect ratios of the crystalsformed in the fertilizer after storage. In another embodiment, thenumber of urea crystals formed in the urea containing fertilizer (e.g.,urea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers) may bereduced by about 10-40% as compared to a fertilizer not comprising ricehulls. In another embodiment, the number of urea crystals formed in theurea containing fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) may be reduced by about 30% as compared to afertilizer not comprising rice hulls. In another embodiment, the numberof urea crystals formed in the urea containing fertilizer (e.g., ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) may bereduced after about 1-8 months of storage as compared a fertilizer notcomprising rice hulls.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts Scanning Electron Micrographs (SEM) images of thesurface of granulated urea formaldehyde reaction product particle thathave been aged for over five months. FIG. 1A is a urea formaldehydereaction product granule surface that has been completely covered withurea crystals during the aging process. Even the areas where activeingredient was applied (brighter white areas) are covered with ureacrystals.

FIG. 1B depicts Scanning Electron Micrographs (SEM) images of thesurface of granulated urea formaldehyde reaction product particle thathave been aged for over five months. FIG. 1B is a surface of a ureaformaldehyde reaction product granule comprising ground rice hulls. Thisformulation has significantly fewer urea crystal growth over the sameaging process period and, in particular, appears to contain no crystalsgrowing over the active ingredient cover areas (brighter white areas).

FIG. 2A depicts the results from non-dropped lumps test and a droppedlumps test for fertilizer stored 6 months using one formulationcomprising 20% ground rice hulls, potassium sulfate, herbicide, andcoated with urea-formaldehyde (UF) resin, and a second formulationcomprising 20% vermiculite, potassium sulfate, mono-ammonium phosphate,herbicide, and coated with UF resin. FIG. 2A shows that the formulationcontaining vermiculite had almost five-times more lumps than the sampleformulated with ground rice hulls when compared using the non-droppedlumps test. Statistical analysis demonstrated this difference wassignificant.

FIG. 2B depicts the results from non-dropped lumps test and a droppedlumps test for fertilizer stored 6 months using one formulationcomprising 20% ground rice hulls, potassium sulfate, herbicide, andcoated with urea-formaldehyde (UF) resin, and a second formulationcomprising 20% vermiculite, potassium sulfate, mono-ammonium phosphate,herbicide, and coated with UF resin. FIG. 2B shows the formulationcontaining vermiculite had approximately forty-four times as many lumpsthan the sample formulated with ground rice hulls when compared usingthe dropped lumps test. Statistical analysis demonstrated thisdifference was significant.

FIG. 3A depicts the surface of a rice hull. FIG. 3B depicts thecross-section of a rice hull. FIG. 3C depicts that the silicaconcentration is concentrated on the surface of the rice hull and isvery thin.

FIG. 4A depicts an elemental map for silicon and carbon of the rice hullsurface.

FIG. 4A shows the X-ray analysis of the silicon and shows that thesilica is located in tight bans on the surface of the rice hulls.

FIG. 4B depicts an elemental map for silicon and carbon of the rice hullsurface. FIG. 4B reflects the X-ray analysis of the carbon and, showsthat, in contrast, the carbon is dispersed throughout the surface of therice hull.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention provides for compositions comprising rice hulls and aurea-based fertilizer, methods of making the compositions, and methodsof using the compositions.

Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as those commonly understood by one of ordinaryskill in the art to which this invention belongs.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise.

“Crystal aspect ratio,” as used herein, refers broadly to the length towidth ratio of a urea crystal, e.g., a urea crystal with a crystalaspect ratio of 50:1 is 50 times as long as it is wide.

“NPK rating,” as used herein, refers broadly to a labeling scheme fordescribing the amount of nitrogen, phosphorus, and potassium. NPKratings consist of three numbers separated by dashes (e.g., 10-10-10 or16-4-8) describes the chemical content of fertilizers. The first numberrepresents the percentage of nitrogen in the product; the second numberrepresents the percentage of phosphorous in the product; the thirdnumber represents the percentage of potassium in the product. The commonform is “N—P—K.”

“SGN,” as used herein, refers broadly to Size Guide Number (SGN). TheSGN is determined by calculating the average particle size of a productgranules in millimeters (mm) and multiplying by 100. For example, 100SGN=1 mm and 1 SGN=10 □m.

Rice Hulls Reduce Caking and Crystal Formation in Urea ContainingFertilizer

The inventor surprisingly discovered, among other things, that the useof ground rice hulls reduces the caking potential of a granulatedfertilizer (e.g., comprising urea containing fertilizer resin).Specifically, the inventor surprisingly found that adding ground ricehulls to a urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) reduced urea crystal growthover time, which, in turn, helps prevent the development of crystalbridges that form the base elements for product caking. The synergisticcombination of ground rice hulls and urea containing fertilizer (e.g.,urea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers) resultsin reduced urea crystal growth during storage of urea containingfertilizer. The lower urea crystal growth also protects anysurface-applied active ingredients (e.g., herbicides), since crystalswill no longer cover the particle surface. The rice hull basedfertilizer granule makes a surprisingly good substrate for transportingactive ingredient due to its relatively small particle size, low bulkdensity, and relatively high absorptivity. Further, the fertilizercompositions described herein also have a lower average odorconcentration as measured by odor unit per cubic meter of air (1o.u./m³) than other fertilizer compositions that do not comprise ricehulls.

Crystal growth in urea-containing fertilizers is a major factor thatcauses caking of such fertilizers over time. For example, when grownfrom relatively pure solutions, urea crystallizes into long needleshaving length to width ratios (crystal aspect ratios) that can exceed50:1. It is believed that these high crystal aspect ratios contributesignificantly to the development of hard caking during typical storageof fertilizers, particularly urea containing fertilizer (e.g., ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers).

Furthermore, when grown from solutions containing methylene urea and/orurea-formaldehyde polymer chains, urea will crystallize into longneedles. See, e.g., Davey, et al. Journal of Crystal Growth 79 (1986):607-613. These long crystal needles contribute to the development ofhard caking during storage of urea containing fertilizers (e.g., ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers). It isbelieved that outward growth of such long crystal needles from thesurface of fertilizer particles enables them to bond with outwardlygrowing crystal needles of other particles causing caking or clumpingeffects. For example, the ability of urea crystals to achieve thecrystal aspect ratios described above causes the urea particles to bondwith other particles causing the particles to lock together intoconcrete-like lumps over time.

Without wishing to be bound to a specific theory, it is believed thatthe rice hulls change the properties of the urea containing fertilizer(e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers). The rice hulls contain a significant amount of amorphoussilica (e.g., about 20% by weight), which blocks crystal growth duringstorage of the fertilizer product. The rice hull amorphous silicainteracts with the urea containing fertilizer (e.g., urea fertilizers orurea formaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) and may disrupt the orderrequired for crystallization, thus interfering with the crystal growthand not merely physically mixed with the urea containing fertilizer(e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers).

The inventor has also surprisingly found that the fertilizercompositions described herein improve active ingredient effectivenessand product performance. The fertilizer compositions described hereinsynergistically provide the active ingredient more quickly andeffectively. The fertilizer compositions described herein provide anunexpected advantage over the prior art technology because they reducecaking during product storage, and achieve greater active ingredientdelivery, resulting in overall improved performance. Thus, thefertilizer compositions described herein result in the delivery of theactive ingredient more quickly and effectively than prior artcompositions. In field applications, the urea crystals must dissolvebefore active ingredient will come in contact with the leaf surface oftarget plant. Since only a limited amount of leaf surface moisture isavailable, in many prior art products, the active ingredient will nevercontact the leaf surface, leading to decreased active ingredientperformance.

Rice Hulls

Rice hulls (or rice husks) are the hard protecting coverings of ricegrains. The hull is formed from hard materials, including opaline silicaand lignin, and protects the rice seed during the growing season. Therice hull contains about 40-50 percent cellulose, 25-30 percent lignin,and 15-20 percent opaline silica, which, together forms a polymericmaterial within rice hull. During the milling processes, the hulls areremoved from the raw grain to yield whole brown rice, which may then befurther milled to remove the bran layer, resulting in white rice.

To form a rice hull, the rice plant take up a soluble silica from thesoil in the form of monosilicic acid and begins storing it in the hull.As the hulls ages, hydrogen bonding between the hydroxyl groups in thesilicic acid and cellulose and lignin becomes established;Cellulose-(C₂H₅(OH))_(x)+Si(OH))₄←Cellulose-((C₂H₅—(OH)₂)_(x)—Si(OH)₃

With further aging, water evaporation begins and the silicic acidpolymerizes with the formation of siloxane bondsSi(OH)₄+Si(OH)₄←Si(OH)₃OSi(OH)₃+H₂O

As polymerization and further water loss continues, amorphous silicabegins to precipitate within the hull, and with continued moisture lossthe opaline silica containing cellulose based polymer forms. Such a highconcentration of silica is very unusual in nature, and the polymericcombination of silica and cellulose-lignin creates a material that ishighly resistant to water penetration and fungal decay. The rice hullsalso have a more acidic pH. The chemical composition and structure ofthe ground rice hulls is markedly different from the rice as it existsin nature.

In order to further define the compositional properties of rice hulls, arice hull was examined using scanning electron microscopy with abackscatter detector. The backscatter detector allows for thedifferentiated between areas with higher and lower atomic number areas.The top portion of a rice hull showed a high concentration of siliconformed the opaline silica deposits (FIG. 3A). This silica deposit doesexist throughout the entire rice hull (FIG. 3B). The inventor found thatthe hulls contain only a thin layer of polymeric silica-cellulose on thevery outside (FIG. 3C).

An x-ray detector was used to identify the elemental composition of aspecific electron image. This analysis confirmed the presence of theopaline silica cellulose polymer as carbon appears uniformly dispersedwithin the area that also display bands of silicon (FIGS. 4A-B).

Without wishing to be bound to a specific theory, the inventor believesthat the distribution of the silica in bands on the surface of the ricehulls provides for direct contact with the urea containing fertilizer(e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers). This direct contact between areas of high silicaconcentration and the urea containing fertilizer (e.g., urea fertilizersor urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) inhibits theformation of urea crystals. This is in contrast with vermiculite, ahydrous silicate mineral, where the silica is more evenly distributedthroughout the mineral structure. Both whole rice grains and vermiculitehave been used as parting agents in urea containing fertilizer (e.g.,urea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers). However,unlike rice hulls, when vermiculite is coated with urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers), the more broadly distributed silica in vermiculite doesnot act to inhibit the formation of urea crystals.

In the fertilizer compositions described herein, the rice hulls may bepresent in a level such that the crystal aspect ratios of the crystalsformed in the fertilizer are significantly reduced to effectivelyeliminate caking in the fertilizer. When the crystal aspect ratio growthrate is impaired, crystal size and relative strength is substantiallyreduced. In addition, the ability of the crystals to bond together isminimized, due to the overall shorter length of each crystal. Thecrystal aspect ratios of the crystals formed in the urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) described herein may be reduced to a level of about 5:1 ascompared to urea containing fertilizer not containing ground rice hulls.The crystal aspect ratios of the crystals formed in the urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) may be reduced to a level of from about 30:1 to about 4:1,for example, 30:1, 27:1, 25:1, 23:1, 20:1, 19:1, 17:1, 16:1, 15:1, 13:1,10:1, 9:1, 8:1, 7:1, 6:1, 5:1, or 4:1. These levels may be observedafter storage, for example after a period of from 1 to 8 months ofstorage, e.g., 1, 2, 3, 4, 5, 6, 7, or 8 months after storage. Further,the urea crystal area formed after storage is reduced as compared tofertilizers not comprising rice hulls. For example, the average crystalarea of urea crystals formed in said fertilizer after 2 months may beless than 30, 40, or 50 μm².

Urea crystal formation in urea-based fertilizer may be measured usingAutomated Segmentation Analysis using, for example, a scanning electronmicroscope (SEM). Scanning electron images of the surface of ureacontaining fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) typically show urea crystal growth afteraging for several months. Automated Segmentation Analysis provides forthe quantitative measurement and counting of the number of crystals onthe surface, without altering the crystals.

The SEM used for acquiring the images of urea crystals may be set withvariable pressure or low pressure operational modes. The standard SEMsample chamber conditions can have pressures of 1×10⁻⁶ Torr at roomtemperature (e.g., about 25° C.). Under these conditions the ratio ofthe vapor pressure of urea and chamber pressure becomes high enough thaturea crystals are unstable and sublimation begins, creating sampleartifacts that eliminate or significantly reduce the measureablequantity of urea crystals. This phenomenon can essentially, destroy theoriginal aged sample integrity, leading to false interpretation of agingeffects. In order the maintain urea crystal stability, a sample chamberpressure should be no greater than 50-80 pascal, with a sampletemperatures ranging from about −25 to −27° C. The sample temperaturemay be maintained using a Peltier cooling stage that operates within theSEM sample chamber.

The first step in the process of measuring crystal formation is toacquire the scanning electron image. The image may be acquired using aquad-coordinate Backscatter detector. This detector provides agrey-scale image of the sample and assigns grey-scale values to specificareas on the image based on the atomic number distribution on thesample. The Backscatter detector also provides topographical imaging ofthe surface of the sample.

The atomic number based grey-scale assignment helps distinguish thecomposition of the crystals, which is primarily urea, from thecomposition of the fertilizer surface. When investigating fertilizerswith particle sizes ranging from 0.5-3.0 mm in mean diameter, it ispreferred to utilize at least 400× magnification and for further crystaldefinition it is more preferred to use a magnification of 1200×.

Once the images have been acquired, they can be imported into an imageanalysis software, such Image Pro Plus (Media Cybernetics, SilverSpring, MD.) The next step is to complete an image segmentation analysiswhere the grey scale pixels assigned to the urea crystals are separatedfrom other grey scale values within the fertilizer surface. The softwareallows for 256 shades of grey for analysis. Assigning a grey scale rangeto the urea crystals may be done by manually looking at the sample imageand comparing that image to a histogram showing the distribution of theshades of grey found in the image. For example, if the urea crystalsappeared to be consistent with a grey scale range 113-120 then thatrange of pixels would be assigned to the area of interest. Once therange is defined for the urea crystals the next step is to remove thebackground pixels. The grey scale pixels of the fertilizer surface aredefined as background, therefore, grey scale ranges 0-112 and 121-256are assigned a completely different color, such as red. This leaves asegmented image with just urea crystals and red background.

The next step is to use the Image Pro Plus software to measure and countthe crystals in the image area. The program employs several mathematicalalgorithms to generate key data values such as, aspect ratio, area,number and statistical values like mean and standard deviation. Thisdata is utilized to establish numerical differences between imagesamples without destroying the integrity of the original sample.

The rice hulls may comminuted in size by grinding. The rice hulls may becomminuted to a size on average of about 20-70 SGN, 30-60 SGN, 45-55SGN, 30-50 SGN, 40-60 SGN, 45-50 SGN, or 50-55 SGN in size. The ricehulls may be comminuted to a size of about 20, 21, 22, 23, 24, 25, 26,27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62,63, 64, 65, 66, 67, 68, 69, or 70 SGN in size. In specific embodiment,the rice hulls may be comminuted to a size of about 48-53 SGN in size.In another specific embodiment, the rice hulls may be comminuted to asize of about 50 SGN in size.

The rice hulls may be present in an amount sufficient to decrease ureacrystal formation in urea-based fertilizer. For example, the rice hullsmay be about 5-50% by weight of the granule. The rice hulls may be about10-40%, 20-30%, 15-30%, 20-35%, 15-40%, 15-30%, 10-20%, 10-25%, 15-25%,15-35%, 25-50%, or 15-50% by weight of the granule. In the fertilizercompositions described herein, the rice hulls may be about 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,45, 46, 47, 48, 49, or 50% by weight of the granule. In specificembodiment, the fertilizer composition may comprise about 10-25% ricehulls by weight of the granule. In another specific embodiment, thefertilizer composition may comprise about 20% rice hulls by weight ofthe granule. The fertilizer composition may be granular, comprising agranule of urea-fertilizer and ground rice hulls.

The fertilizer granules may comprise rice hulls and a urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers). For example, the granule may comprise ground rice hullsand urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers). The ground rice hulls may besprayed or soaked in methylene urea to coat them with theurea-fertilizer.

The fertilizer composition may comprise granules comprising rice hullsand a urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers). The granules may furthercomprise other components, including but not limited to macronutrients,micronutrients, carriers (e.g., inert solid carriers), biostimulants,and other fertilizers. These components may be part of the granule orthey may be admixed with the granules comprising rice hulls and a ureacontaining fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers).

Fertilizer Components

The fertilizer compositions described herein may comprise threemacronutrients: nitrogen (N), phosphorus (P), potassium (K); threesecondary macronutrients: calcium (Ca), magnesium (Mg), and sulfur (S);and micronutrients including, but not limited to, copper (Cu), iron(Fe), manganese (Mn), molybdenum (Mo), zinc (Zn); nickel (Ni), boron(B), silicon, cobalt (Co), and mixtures thereof.

The fertilizer components may be present in an amount sufficient toprovide nutrients to a plant to support growth. The fertilizercomponents may range from about 1 to about 40% by weight elementalnitrogen (N) (preferably, about 15-36% by weight); about 1 to about 30%by weight phosphorous, e.g., as P₂O₅ (preferably, about 1-27% byweight); and about 1 to about 30% by weight potassium, e.g., as K₂O(preferably, about 3-15% by weight). The micronutrient content of thefertilizer ingredient may range from about 1 to about 60,000 ppm (partsper million). For example, the micronutrient content may be about 10 to20,000 ppm (parts per million).

The fertilizer compositions described herein may be a single nutrientfertilizer, comprising, for example, urea. The fertilizer compositionsdescribed herein may be a binary nutrient fertilizer providing both anitrogen and phosphorous source. The fertilizer compositions describedherein may be a NPK nutrient fertilizer providing both a nitrogen,potassium, and phosphorous source.

The fertilizer compositions described herein may comprisemicronutrients. For example, the fertilizer compositions may comprisepotassium sulfate, micro elements, mono-ammonium phosphate, potassiumchloride, or mixtures thereof. The fertilizer compositions may comprisecalcium nitrate, ammonium sulfate, isobutylidene dirurea, ammoniumnitrate, ureaform, methylene urea, urea, anhydrous ammonia, polymercoated urea (e.g. sulfur coated urea) ammonium polyphosphate,monoammonium phosphate, iron, diammonium phosphate, potassium nitrate,or mixtures thereof.

In one embodiment, the fertilizer composition may comprise granulescomprising ground rice hulls coated with a urea containing fertilizerresin (e.g., a resin of urea fertilizers or urea formaldehyde reactionproduct fertilizers such as urea-formaldehyde fertilizer or methyleneurea fertilizers), potassium sulfate, ammonium sulfate,3,6-Dichloro-2-methoxybenzoic acid (dicamba), 2,4-dichlorophenoxy aceticacid (2,4-D), and/or methyl chlorophenoxy propionic acid (MCPP-P). Forexample, the granule may comprise 40-60% by weight urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) and 10-25% by weight ground rice hulls, e.g., about 58% byweight urea containing fertilizer and 20% by weight ground rice hulls.The granule may comprise about 5-10% by weight potassium sulfate, e.g.,about 6.5% by weight potassium sulfate. The granule may comprise about10-20% by weight ammonium sulfate, e.g., about 13.5% by weight ammoniumsulfate. The granule may comprise about 0.5-4% by weight2,4-dichlorophenoxy acetic acid (2,4-D), e.g., about 1.25% 2,4-D,0.04-0.2% by weight 3,6-Dichloro-2-methoxybenzoic acid (dicamba), and/or0.5-1.5% by weight methyl chlorophenoxy propionic acid (MCPP-P), e.g.,about 0.7% MCPP-P.

In one embodiment, the fertilizer composition may further comprisepotassium sulfate, ammonium sulfate, 3,6-Dichloro-2-methoxybenzoic acid(dicamba), 2,4-dichlorophenoxy acetic acid (2,4-D), and/or methylchlorophenoxy propionic acid (MCPP-P). For example, the fertilizercomposition may comprise about 5-10% by weight potassium sulfate, e.g.,about 6.5% by weight potassium sulfate. The fertilizer composition maycomprise about 10-20° A by weight ammonium sulfate, e.g., about 13.5% byweight ammonium sulfate. The fertilizer composition may comprise about0.5-4% by weight 2,4-dichlorophenoxy acetic acid (2,4-D), e.g., about1.25% 2,4-D, 0.04-0.2% by weight 3,6-Dichloro-2-methoxybenzoic acid(dicamba), and/or 0.5-1.5% by weight methyl chlorophenoxy propionic acid(MCPP-P), e.g., about 0.7% MCPP-P.

The fertilizer compositions described herein may comprise methylene urea(MU) resin. The MU resin may have an urea to formaldehyde ratio of about1.5:1 to 8:1. The urea to formaldehyde ratio may be from about 1.5:1 toabout 8:1, for example, 1.5:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, or 8:1. Theurea to formaldehyde ratio may be about 4:1.

The fertilizer compositions described herein may comprise less than 1,less than 2, less than 3, less than 4, less than 5, less than 6, lessthan 7, less than 8, less than 9, less than 10, less than 11, less than12, less than 13, less than 14, less than 15, less than 16, less than17, less than 18, or less than 20% water by weight of the composition.In a specific embodiment, the fertilizer compositions described hereinmay comprise less than 5% water by weight of the composition.

The fertilizer compositions described herein encompass a wide variety offertilizer forms including, but not limited to granules, particles, orpellets (referred to collectively as fertilizer granule). The physicalforms of the fertilizer compositions described herein include granulesand extruded particles. The fertilizer compositions described herein maybe a granular composition. Fertilizer granule sizes may range from about0.5 to about 5.0 mm diameter (e.g., about 0.5-2 mm). Fertilizer granulesizes may range from about 1.0 to about 5.0 mm diameter (e.g., about1-3.0 mm). Fertilizer granule sizes may range from about 0.5 to about 2mm (e.g., about 1.0-5.0 mm).

The granular particles may be about 0.5-5 mm in size, for example, 0.5,0.6, 0.7, 0.8, 0.9, 1, 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, 4, 5 mmin size. The granular particles may be about 1-5, 1-2, 0.5-5, 0.5-2,1-3, 2-5, 1-4, 2-4, or 3-5 mm in size. In another specific embodiment,the granular particles may be about 0.5-4 mm in size as measured bydiameter.

The fertilizer compositions described herein may be a controlled releasefertilizer.

The fertilizer compositions described herein may be admixed withherbicides, micronutrients, biostimulants, soil amendments, and inertsolid carriers.

Inert solid carriers may be admixed with the fertilizer components toproduce a composition described herein. Suitable inert solid carriermaterials include a variety of organic and/or inorganic materials, whichabsorb or which may be coated with the active ingredient and that havebeen appropriately ground/fractionated/sized, may be employed herein.Suitable organic materials include but are not limited to corncobs,peanut hulls, processed paper pulp, sawdust, and mixtures thereof.Suitable inorganic materials include limestone, gypsum, sand,vermiculite, perlite, fuller's earth and clays such as attapulgiteclays, bentonite clays, montmorillonite clays, and mixtures thereof.

The fertilizer compositions may be admixed with herbicides including,but not limited to, 2,4-dichlorophenoxy acetic acid (2,4-D), methylchlorophenoxy propionic acid (MCPP-P), 3,6-Dichloro-2-methoxybenzoicacid (dicamba), amide herbicides including, but not limited to,allidochlor, beflubutamid, benzadox, benzipram, bromobutide,cafenstrole, CDEA, chlorthiamid, cyprazole, dimethenamid,dimethenamid-P, diphenamid, epronaz, etnipromid, fentrazamide, flupoxam,fomesafen, halosafen, isocarbamid, isoxaben, napropamide, napropamide-N,naptalam, pethoxamid, propyzamide, quinonamid, saflufenacil, tebutam andtiafenacil; anilide herbicides including, but not limited to,chloranocryl, cisanilide, clomeprop, cypromid, diflufenican,etobenzanid, fenasulam, flufenacet, flufenican, mefenacet, mefluidide,metamifop, monalide, naproanilide, pentanochlor, picolinafen andpropanil; arylalanine herbicides including, but not limited to,benzoylprop, flamprop and flamprop-M; chloroacetanilide herbicidesincluding, but not limited to, acetochlor, alachlor, butachlor,butenachlor, delachlor, diethatyl, dimethachlor, metazachlor,metolachlor, S-metolachlor, pretilachlor, propachlor, propisochlor,prynachlor, terbuchlor, thenylchlor and xylachlor; sulfonanilideherbicides including, but not limited to, benzofluor, perfluidone,pyrimisulfan and profluazol; sulfonamide herbicides including, but notlimited to, asulam, carbasulam, fenasulam and oryzalin; antibioticherbicides including, but not limited to, bilanafos; benzoic acidherbicides such as chloramben, dicamba, 2,3,6-TBA and tricamba;pyrimidinyloxybenzoic acid herbicides including, but not limited to,bispyribac and pyriminobac; pyrimidinylthiobenzoic acid herbicidesincluding, but not limited to, pyrithiobac; phthalic acid herbicidesincluding, but not limited to, chlorthal; picolinic acid herbicidesincluding, but not limited to, aminopyralid, clopyralid, halauxifen andpicloram; quinolinecarboxylic acid herbicides including, but not limitedto, quinclorac and quinmerac; benzoylcyclohexanedione herbicidesincluding, but not limited to, mesotrione, sulcotrione and tembotrione;benzofuranyl alkylsulfonate herbicides including, but not limited to,benfuresate and ethofumesate; carbamate herbicides including, but notlimited to, asulam, carboxazole, chlorprocarb, dichlormate, fenasulam,karbutilate and terbucarb; carbanilate herbicides including, but notlimited to, barban, BCPC, carbasulam, carbetamide, CEPC, chlorbufam,chlorpropham, CPPC, desmedipham, phenisopham, phenmedipham,phenmedipham-ethyl, propham and swep; cyclohexene oxime herbicidesincluding, but not limited to, alloxydim, butroxydim, clethodim,cloproxydim, cycloxydim, profoxydim, sethoxydim, tepraloxydim andtralkoxydim; cyclopropylisoxazole herbicides such as isoxachlortole andisoxaflutole; dicarboximide herbicides including, but not limited to,benzfendizone, cinidon-ethyl, flumezin, flumiclorac, flumioxazin andflumipropyn; dinitroaniline herbicides including, but not limited to,benfluralin, butralin, dinitramine, ethalfluralin, fluchloralin,isopropalin, methalpropalin, nitralin, oryzalin, pendimethalin,prodiamine, profluralin and trifluralin; dinitrophenol herbicidesincluding, but not limited to, dinofenate, dinoprop, dinosam, dinoseb,dinoterb, DNOC, etinofen and medinoterb; diphenyl ether herbicidesincluding, but not limited to, ethoxyfen; nitrophenyl ether herbicidesincluding, but not limited to, acifluorfen, aclonifen, bifenox,chlomethoxyfen, chlornitrofen, etnipromid, fluorodifen, fluoroglycofen,fluoronitrofen, fomesafen, furyloxyfen, halosafen, lactofen, nitrofen,nitrofluorfen and oxyfluorfen; dithiocarbamate herbicides including, butnot limited to, dazomet and metam; halogenated aliphatic herbicidesincluding, but not limited to, alorac, chloropon, dalapon, flupropanate,hexachloroacetone, iodomethane, methyl bromide, monochloroacetic acid,sodium chloroacetate an trichloroacetic acid; imidazolinone herbicidesincluding, but not limited to, imazamethabenz, imazamox, imazapic,imazapyr, imazaquin and imazethapyr; inorganic herbicides including, butnot limited to, ammonium sulfamate, borax, calcium chlorate, coppersulfate, ferrous sulfate, potassium azide, potassium cyanate, sodiumazide, sodium chlorate and sulfuric acid; nitrite herbicides such asbromobonil, bromoxynil, chloroxynil, dichlobenil, iodobonil, ioxynil andpyraclonil; organophosphorous herbicides including, but not limited to,amiprofos-methyl, anilofos, bensulide, bilanafos, butamifos, 2,4-DEP,DMPA, EBEP, fosamine, glufosinate, glufosinate-P, glyphosate andpiperophos; oxadiazolone herbicides including, but not limited to,dimefuron, methazole, oxadiargyl and oxadiazon; oxazole herbicidesincluding, but not limited to, carboxazole, fenoxasulfone, methiozolinand pyroxasulfone; phenoxy herbicides including, but not limited to,bromofenoxim, clomeprop, 2,4-DEB, 2,4-DEP, difenopenten, disul, erbon,etnipromid, fenteracol and trifopsime; phenoxyacetic herbicidesincluding, but not limited to, 2,4-D, MCPA, MCPA-thioethyl and 2,4,5-T;phenoxybutyric herbicides; phenoxypropionic herbicides including, butnot limited to, cloprop, 4-CPP, dichlorprop, dichlorprop-P, 3,4-DP,fenoprop, mecoprop and mecoprop-P; aryloxyphenoxypropionic herbicidesincluding, but not limited to, chlorazifop, clodinafop, clofop,cyhalofop, diclofop, fenoxaprop, fenoxaprop-P, fenthiaprop, fluazifop,fluazifop-P, haloxyfop, haloxyfop-P, isoxapyrifop, metamifop,propaquizafop, quizalofop, quizalofop-P and trifop; phenylenediamineherbicides including, but not limited to, dinitramine and prodiamine;phenyl pyrazolyl ketone herbicides including, but not limited to,benzofenap, pyrazolynate, pyrasulfotole, pyrazoxyfen and topramezone;pyrazolylphenyl herbicides including, but not limited to, fluazolate,pinoxaden and pyraflufen; pyridazine herbicides including, but notlimited to, credazine, pyridafol and pyridate; pyridazinone herbicidessuch as brompyrazon, chloridazon, dimidazon, flufenpyr, metflurazon,norflurazon, oxapyrazon and pydanon; pyridine herbicides including, butnot limited to, aminopyralid, cliodinate, clopyralid, dithiopyr,fluroxypyr, haloxydine, picloram, picolinafen, pyriclor, thiazopyr andtriclopyr; pyrimidinediamine herbicides including, but not limited to,iprymidam and tioclorim; quaternary ammonium herbicides including, butnot limited to, cyperquat, diethamquat, difenzoquat, diquat, morfamquatand paraquat; thiocarbamate herbicides including, but not limited to,butylate, cycloate, di-allate, EPTC, esprocarb, ethiolate, isopolinate,methiobencarb, molinate, orbencarb, pebulate, prosulfocarb,pyributicarb, sulfallate, thiobencarb, tiocarbazil, tri-allate andvernolate; thiocarbonate herbicides including, but not limited to,dimexano, EXD and proxan; thiourea herbicides including, but not limitedto, methiuron; triazine herbicides such as dipropetryn, triaziflam andtrihydroxytriazine; chlorotriazine herbicides including, but not limitedto, atrazine, chlorazine, cyanazine, cyprazine, eglinazine, ipazine,mesoprazine, procyazine, proglinazine, propazine, sebuthylazine,simazine, terbuthylazine and trietazine; fluoroalkyltriazine herbicidesincluding, but not limited to, indaziflam and traiziflam;methoxytriazine herbicides including, but not limited to, atraton,methometon, prometon, secbumeton, simeton and terbumeton;methylthiotriazine herbicides including, but not limited to, ametryn,aziprotryne, cyanatryn, desmetryn, dimethametryn, methoprotryne,prometryn, simetryn and terbutryn; triazinone herbicides including, butnot limited to, ametridione, amibuzin, hexazinone, isomethiozin,metamitron and metribuzin; triazole herbicides such as amitrole,cafenstrole, epronaz and flupoxam; triazolone herbicides including, butnot limited to, amicarbazone, bencarbazone, carfentrazone, flucarbazone,propoxycarbazone, sulfentrazone and thiencarbazone-methyl;triazolopyrimidine herbicides including, but not limited to,cloransulam, diclosulam, florasulam, flumetsulam, metosulam, penoxsulam;pyroxsulam; uracil herbicides including, but not limited to,butafenacil, bromacil, flupropacil, isocil, lenacil and terbacil;3-phenyluracils; urea herbicides including, but not limited to,benzthiazuron, cumyluron, cycluron, dichloralurea, diflufenzopyr,isonoruron, isouron, methabenzthiazuron, monisouron and noruron;phenylurea herbicides including, but not limited to, anisuron, buturon,chlorbromuron, chloreturon, chlorotoluron, chloroxuron, daimuron,difenoxuron, dimefuron, diuron, fenuron, fluometuron, fluothiuron,isoproturon, linuron, methiuron, methyldymron, metobenzuron,metobromuron, metoxuron, monolinuron, monuron, neburon, parafluron,phenobenzuron, siduron, tetrafluron and thidiazuron;pyrimidinylsulfonylurea herbicides including, but not limited to,amidosulfuron, azimsulfuron, bensulfuron, chlorimuron, cyclosulfamuron,ethoxysulfuron, flazasulfuron, flucetosulfuron, flupyrsulfuron,foramsulfuron, halosulfuron, imazosulfuron, mesosulfuron, nicosulfuron,orthosulfamuron, oxasulfuron, primisulfuron, propyrisulfuron,pyrazosulfuron, rimsulfuron, sulfometuron, sulfosulfuron andtrifloxysulfuron; triazinylsulfonylurea herbicides such aschlorsulfuron, cinosulfuron, ethametsulfuron, iodosulfuron, metsulfuron,prosulfuron, thifensulfuron, triasulfuron, tribenuron, triflusulfuronand tritosulfuron; thiadiazolylurea herbicides including, but notlimited to, buthiuron, ethidimuron, tebuthiuron, thiazafluron andthidiazuron; herbicides including, but not limited to, acrolein, allylalcohol, azafenidin, benazolin, bentazone, benzobicyclon, buthidazole,calcium cyanamide, cambendichlor, chlorfenac, chlorfenprop,chlorflurazole, chlorflurenol, citmethylin, clomazone, CPMF, cresol,ortho-dichlorobenzene, dimepiperate, endothal, fluoromidine, fluridone,flurochloridone, flurtamone, fluthiacet, indanofan, methazole, methylisothiocyanate, nipyraclofen, OCH, oxadiargyl, oxadiazon,oxaziclomefone, pentachlorophenol, pentoxazone, phenylmercury acetate,pinoxaden, prosulfalin, pyribenzoxim, pyriftalid, quinoclamine,rhodethanil, sulglycapin, thidiazimin, tridiphane, trimeturon,tripropindan and tritac; or mixtures thereof.

The fertilizer compositions can be applied at various rates to achievethe desired effect of weed control and turf safety. In general, aminimum of about 0.1-3 lb, e.g, about 1.5 lb active ingredient (e.g.,2,4-dichlorophenoxy acetic acid (2,4-D)) per acre is required to controlweeds in turfgrass under the wide range of conditions that areexperienced in growing turf, such as geographical location, temperature,soil moisture, weed species and stage of growth, and other factors.

The invention also provides for soil, soil amendments, and soiladditives comprising the compositions described herein.

The fertilizer compositions described herein have a lower average odorconcentration, as measured by odor unit per cubic meter of air (1o.u./m³), than other fertilizer compositions that do not comprise ricehulls. For example, the fertilizer compositions described herein mayhave less than 600 o.u./m³, less than 590 o.u./m³, less than 580o.u./m³, less than 570 o.u./m³, less than 560 o.u./m³, less than 550o.u./m³, or less than 540 o.u./m³. In other embodiments, the fertilizercompositions have an average odor concentration of 530-550 o.u./m³ or530-540 o.u./m³.

Methods of Making

The fertilizer compositions described herein may be manufactured byspraying urea containing fertilizer resin (e.g., a resin of ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) onto ricehulls and forming a granule. The rice may be hulled by dry milling orparboiling to yield rice hulls. The rice hulls may be ground to reducethem in size to any of the sizes discussed herein, such as about 20-70SGN, about 30-60 SGN in size, or about 50 SGN in size, for example about40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57,58, 59, or 60 SGN. Rice hulls may be granulated using a rotating drum,fluidized bed, pan, pug mill, or pellet mill. Fertilizer nutrients,including but not limited to, potassium sulfate, micro elements,mono-ammonium phosphate, potassium chloride, or mixtures thereof may beadded to the fertilizer composition.

The fertilizer compositions described herein may be produced byemploying any of a variety of processes. For example, a urea containingfertilizer resin (e.g., a resin of urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) can be applied to a ground rice hulls using:(a) a spray mixture with solvents and/or surfactants; (b) adhered to theouter surface of the rice hull granules with an adhesive/sticking agent;(c) incorporated into a mixture of dry ingredients and a liquid, andthen extruded or molded into discrete particles; or (d) impregnated intoa porous granule.

Specifically, the fertilizer compositions described herein may beprepared by mixing urea containing fertilizer resin (e.g., a resin ofurea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers) ineffective amounts with rice hulls (for example, in a rotating drumcontainer) for a sufficient period of time, e.g., 1-10 minutes, untilthe urea containing fertilizer resin (e.g., a resin of urea fertilizersor urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) is uniformlycoated on and absorbed into the rice hull granules. In one embodiment,the fertilizer composition manufactured may be granular with a particlesize of about 0.5-10 mm, e.g., 0.8-4 mm. In an embodiment, thegranulation may be done in a rotating drum at a temperature from about100-200° F., for example 130-160° F. In an embodiment, the granulationmay be performed in a series of rotating drums at a temperature of about130-160° F.

Other optional methods which may be employed for producing compositionscontaining urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) and granular rice hullsinclude: dissolving a urea containing fertilizer resin (e.g., a resin ofurea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers)concentrate in a liquid solvent/surfactant blend, e.g., water to makeaqueous resin solution, then spraying this mixture onto ground ricehulls so the solution is uniformly absorbed on the substrate particles;or using urea containing fertilizer (e.g., urea fertilizers or ureaformaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) in a dry powder state, tackingthis onto the surface of a fertilizer and/or inert carrier material,such as ground rice hulls, using a liquid sticking agent or adhesive toobtain a uniform distribution of the urea containing fertilizer (e.g.,urea fertilizers or urea formaldehyde reaction product fertilizers suchas urea-formaldehyde fertilizer or methylene urea fertilizers) over thesubstrate particles (e.g., ground rice hulls). For example, a moltenurea containing fertilizer resin (e.g., a resin of urea fertilizers orurea formaldehyde reaction product fertilizers such as urea-formaldehydefertilizer or methylene urea fertilizers) at a temperature of about270-275° F. may be sprayed onto the rice hulls. See U.S. Pat. Nos.5,102,440; 6,254,655; and 8,288,320, each of which are hereinincorporated by reference in their entireties.

A method of making a soil comprising any of the compositions describedherein is provided. In one embodiment, the method comprises admixing asoil with any of compositions described herein to form a soil comprisingthe compositions described herein.

Methods of Use

The fertilizer compositions described herein may be used to delivernutrients to a plant. For example, a method of fertilizing a plant maycomprise adding the fertilizer composition described herein to a plant.A method of feeding a plant may comprise adding the fertilizercomposition described herein to a plant. A method of promoting plantgrowing may comprise adding the fertilizer composition described hereinto a plant. The fertilizer compositions described herein an unexpectedadvantage over the prior art technology because the reduction in cakingduring product storage allows for achieves greater active ingredientdelivery and thus, performance.

The fertilizer compositions described herein may be used in methods offeeding, promoting plant growth, or fertilizing a plant life comprisingadding the fertilizer composition described herein to a plant life or anarea containing the plant life. An area containing a plant life mayinclude a lawn or garden.

A method of growing a plant life is also provided. In one embodiment,the method comprises growing a plant life in soil comprising any of thecompositions described herein. In another embodiment, the methodcomprises preparing a soil comprising any of the compositions describedherein and planting a plant life in said soil.

A method for reducing crystal formation after storage in a urea-basedfertilizer comprising forming granules comprising rice hulls, and ureacontaining fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) resin. In another embodiment, a method forreducing the average crystal area formed after storage in a urea-basedfertilizer comprising forming granules comprising rice hulls, and ureacontaining fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers). In one embodiment, the rice hulls may beground rice hulls, preferably about 40-60 SGN in size. In anotherembodiment, the storage may be for 1-8 months, e.g., 1, 2, 3, 4, 5, 6,7, or 8 months.

A method for reducing the number of urea crystals formed in a fertilizermay comprise adding rice hulls in an amount sufficient to lower thecrystal aspect ratios of the crystals formed in the fertilizer afterstorage. The number of urea crystals formed in the urea containingfertilizer (e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) may be reduced by about 10-40% as compared to a fertilizernot comprising rice hulls. The number of urea crystals formed in theurea containing fertilizer (e.g., urea fertilizers or urea formaldehydereaction product fertilizers such as urea-formaldehyde fertilizer ormethylene urea fertilizers) may be reduced by about 10%, 15%, 20%, 25%,30%, 35%, or 40% as compared to a fertilizer not comprising rice hulls.The number of urea crystals formed in the urea containing fertilizer(e.g., urea fertilizers or urea formaldehyde reaction productfertilizers such as urea-formaldehyde fertilizer or methylene ureafertilizers) may be reduced after about 1-8 months of storage ascompared a fertilizer not comprising rice hulls. The number of ureacrystals formed in the urea containing fertilizer (e.g., ureafertilizers or urea formaldehyde reaction product fertilizers such asurea-formaldehyde fertilizer or methylene urea fertilizers) may bereduced after about 1, 2, 3, 4, 5, 6, 7, or 8 months of storage ascompared a fertilizer not comprising rice hulls.

A method for increased weed control as compared to a fertilizercomposition not comprising rice hulls comprising adding a fertilizercomposition described herein to a plant life. The weed control may beimproved by about 10, 15, 20, 25, 30, 35, 40, 45, or 50% as compared toa fertilizer composition not comprising rice hulls.

The plant life may be a plant, plant cutting, or seed. The plant may beyoung plant, transplant, or seedling.

All publications (e.g., Non-Patent Literature), patents, patentapplication publications, and patent applications are hereinincorporated by reference to the same extent as if each individualpublication, patent, patent application publication, or patentapplication was specifically and individually indicated to beincorporated by reference.

Although methods and materials similar or equivalent to those describedherein may be used in the invention or testing of the present invention,suitable methods and materials are described herein. The materials,methods and examples are illustrative only, and are not intended to belimiting.

The following examples are included merely for purposes of illustrationof certain aspects and embodiments of the present invention, and are notintended to limit the invention.

EXAMPLES Example 1

Rice Hull Urea Containing Fertilizer Composition

Rice hulls were ground and classified to a −20 Mesh/+80 mesh sizefraction, yielding an average particle size of 30-40 SGN. The groundhulls were then formulated with methylene urea resin using a granulationprocess. The amount of ground rice hulls was about 15-25% by weight ofthe entire formulation. The granulation process was conducted by addingdry ground rice hulls, along with other dry fertilizer nutrients suchpotassium sulfate, micro elements, mono-ammonium phosphate, or potassiumchloride and spraying the solids with a molten methylene urea resin. Theresin served as a binder to help form granules, in addition to afertilizer ingredient. The methylene urea resin temperature was in arange of 270-275° F., and containing less than 5% moisture. Themethylene urea resin was formulated with a urea to formaldehyde ratio of4:1 to 8:1. The granulation process was conducted in a rotating drum ata temperature from 130-160° F.

Once the granulation process was completed, the materials were screenedto a size most appropriate for a given product category. The size anddensity of the rice hulls makes it possible to manufacture highlyeffective granular weed control products, using granulation technology.Size −14 mesh +50 mesh was used and provided a good combination ofagronomic performance and processability.

Once the granulation process and screening was completed, an activeingredient solution or melt was applied to the surface using acontinuous or batch mixer/blender.

The fertilizer composition comprising granulated methylene ureafertilizer/ground rice hulls (“Experimental”) and granulated methyleneurea fertilizer (used as a control, “Current”) were aged for 5 months.The fertilizers were then examined for the appearance of crystals andthe size of the crystals before and after aging. The crystals weremeasured using Automated Segmentation Analysis as described herein.

TABLE 1 Crystal Formation Crystal Area Crystals Sample DescriptionAdditive Type (μm²) Counted (#) Fresh TB + 2, Current None 7.46 477 AgedTB + 2, Current None 97.33 1,976 Fresh TB + 2, Rice Hulls 16.36 612Experimental Aged TB + 2, Rice Hulls 30.49 1,149 Experimental

As shown above, the addition of ground rice hulls significantly reducedthe crystal area and crystals counted compared to a fertilizercomposition lacking rice hulls after five months of storage. As such,the ground rice hulls significantly reduced urea crystal growth. Thislower crystal growth helped prevent the development of crystal bridges,which form from the base elements of product caking.

Example 2

Urea Crystal Inhibition

Formulation samples prepared with 20% rice hulls, potassium sulfate,herbicide, and coated with urea-formaldehyde resin were placed intoindividual bags weighing 14.29 pounds each. These bags were palletizedand stacked with 80 bags on each pallet. The pallets were then stackedfour high and placed in a warehouse in order to evaluate storagestability. A similar formulation, prepared with 20% vermiculite,potassium sulfate, mono-ammonium phosphate, herbicide, and coated withurea-formaldehyde resin was placed into individual bags weighing 14.29pounds each. This formulation was palletized and stored in the samemanner as the rice hull based formula.

Following six months of storage in the warehouse, bags were removed fromthe 2-down pallet and the 4-down pallet for evaluation. The primarymethod of evaluation was to establish the weight of fertilizer lumpsthat would not pass through a 4-mesh screen. The lumps correspond tocrystal formation. More crystal formation increases the agglomeration ofurea crystals to form lumps, e.g., very large collections of ureacrystals. The weight evaluation was conducted on bags that were nothandled prior to weighing the lumps: non-dropped Lumps (FIG. 2A). Inaddition, the weight evaluation was conducted after dropping the eachbag from a waist high position one time. This dropped test simulates atypical consumer handling scenario. The weight evaluation on the handledbags was referred to, Dropped Lumps. Each test included 40 data points(FIG. 2B).

MiniTab statistical software was used to analyze the raw data. Box plotswere utilized to show the data sample distribution and the boxes contain75% of the data values. The final data tails are shown by whisker linesand/or single points. The mean value is shown by the solid circle withinthe box. The means were compared using one-way ANOVA and Tukey methods.Means that do not share a letter are considered significantly different.

The fertilizer composition comprising rice hulls had significantly fewernon-dropped lumps and dropped lumps after 6 months of storage ascompared to a fertilizer composition comprising vermiculite. Thefertilizer compositions comprising rice hulls and a urea-basedfertilizer surprisingly provided lower crystal formation and smallercrystals over a 6 month-storage period as compared to a urea-basedfertilizer alone.

Example 3

Field Test Data On Weed Control

Herbicide control efficacy trials were conducted comparing a methyleneurea based fertilizer with an herbicide without ground ricehulls—Granular Weed & Feed “Granular W&F” was compared to a methyleneurea based fertilizer with an herbicide with 20% ground rice hulls byweight—“Rice Hull W&F.” The fertilizer application rate for bothmaterials was 0.8 Lbs. nitrogen per 1,000 square feet. The herbicideincluded in both materials was 1.5 Lbs. of 2,4-dichlorophenoxy aceticacid (2,4-D) and 1.5 Lbs. of methyl chlorophenoxy propionic acid(MCPP-P) per acre. The materials were applied to a Kentucky bluegrassarea infested with Dandelion (Taraxacum officinale) and White clover(Trifolium repens).

The treatments were weighed in grams prior to application to maintainaccurate product delivery rate and applied using a standardized screendistribution box which covered each test plot area. All treatments wereapplied on dew moistened foliage. Table 1 shows the results of trialsconducted to determine Dandelion control and Table 2 shows the resultsof trials conducted to determine White clover control. All trials werereplicated and weed control evaluations were conducted one month afterapplication.

TABLE 2 Dandelion (Taraxacum officinale) Control Dandelion (Taraxacumofficinale) Control (%)-One Month After Application Trial A B C D E F GH Untreated 0.0 c* 0.0 c 0.0 c 0.0 c 0.0 c 0.0 c 0.0 c 0.0 c ControlGranular W&F 17.5 b 22.5 b 47.5 b 25.0 b 35.0 b 43.8 b 37.5 b 41.3 bRice Hulls 52.5 a 42.5 a 75.0 a 50.0 a 77.5 a 86.3 a 78.8 a 76.3 a W&F*Means followed by same letter do not significantly differ (P = 0.05,LSD)

The surprising results showed that the “Rice Hull W&F” controlledDandelions at a rate of 1.6-3.0 times greater than “Granular W&F.”

TABLE 3 White Clover (Trifolium repens) White clover (Trifolium repens)Control (%)-One Month After Application Trial A B C D Untreated Control0.0 b* 0.0 c 0.0 c 0.0 b Granular W&F 20.0 b 36.3 b 60.0 b 20.0 b RiceHulls W&F 63.8 a 88.8 a 78.8 a 67.5 a *Means followed by same letter donot significantly differ (P = 0.05, LSD)

The results from trials conducted to determine extent of White clovercontrol indicated the “Rice Hulls W&F” controlled White clover a rate of1.3-3.4 times greater than “Granular W&F.”

The fertilizer compositions comprising granules comprising rice hullsand a urea-based fertilizer surprisingly provided better weed control ascompared to a urea-based fertilizer alone.

As discussed herein, the lower urea crystal growth also protects anysurface applied active ingredients, since crystal will no longer coverthe particle surface. In a field application, these urea crystals mustdissolve before the active ingredient will come into contact with thetarget surface. Since there is only a limited amount of leaf surfacemoisture available, in many cases the active ingredient will never comein contact with the target surface, leading to decreased activeingredient performance. Therefore, another advantage of the fertilizercomposition comprising ground rice hulls is that improved activeingredient effectiveness and product performance.

Example 4

Odor Analysis Study Summary

The odors from three fertilizer products, (1) a urea-based fertilizer“fertilizer,” (2) a fertilizer with an herbicide without ground ricehulls—Granular Weed & Feed “Granular W&F,” (3) a methylene urea basedfertilizer with an herbicide with 20% ground rice hulls by weight—“RiceHull W&F,” were evaluated. Both Granular W&F and Rice Hull W&F containedabout 1.21% 2,4-Dichlorophenoxy Acetic Acid (2,4-D) by weight and 0.61%Methyl Chlorophenoxy Propionic Acid (MCPP-P) by weight herbicides. BothGranular W&F and Rice Hull W&F were prepared to have about 28% nitrogenby weight and about 3% K₂O by weight. The odor characterization was doneby olfactometric analysis on odorous samples prepared from the threeproducts. The analysis provided the overall odor concentration.

Experimental Methods & Results

In order to capture odorous gas from each of the three samples, equalweights of each were placed in a small pan. Each pan is then covered bya gas flux chamber were a controlled flow of nitrogen gas introducedinto the chamber. Simultaneously, the air is withdrawn into a 60 literNalophan sample bag. Three air samples were collected for each productunder evaluation. The gas samples are adjusted to normalized temperatureand pressure for olfactometry (P=101.3 kPa and T=293 K). The notationNm³ indicates the use of normalized gas.

The odors from the gas samples are quantified by olfactometericanalysis, which determines the olfactory perception threshold of agaseous sample. The olfactory perception threshold is defined as thenumber of dilutions at which 50% of a panel perceives the odor while 50%do not perceive the odor. By definition, the olfactory perceptionthreshold is equivalent to 1 odor unit per cubic meter of air ‘1o.u./m³’. The number of dilutions of the odor sample required to obtain1 o.u./m³ indicates the odor concentration of the sample. Based on theseparameters, the odor concentration of each sample was tested and Table 4summarizes the results.

TABLE 4 Odor Concentrations Measured Product Average Odor Concentrations[o.u./Nm³] Fertilizer Only 651 Granular W&F 557 Rice Hull W&F 534

The Rice Hulls W&F had the lowest mean value of 534 o.u./Nm³. Thefertilizer only, had the highest mean value of 651 o.u./Nm³. Thus, theaddition of ground rice hulls to the granules surprisingly reduced theproduction of volatile organic compounds that may be detected by humansas an odor.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

I claim:
 1. A fertilizer composition comprising granules comprising ricehulls and a urea containing fertilizer, wherein the urea containingfertilizer is uniformly coated directly on an outer surface of the ricehulls, uniformly adhered directly on the outer surface of the ricehulls, or impregnated into the rice hulls.
 2. The composition of claim1, wherein said urea containing fertilizer is a urea formaldehydereaction product fertilizer.
 3. The composition of claim 2, wherein saidurea containing fertilizer is a methylene urea fertilizer.
 4. Thecomposition of claim 2, wherein said urea containing fertilizer is aurea-formaldehyde fertilizer.
 5. The composition of claim 1, whereinsaid rice hulls are about 20-70 SGN.
 6. The composition of claim 1,wherein the fertilizer composition, when stored over 1, 2, 3, 4, 5, 6,7, or 8 months, has a reduced crystal aspect ratio compared to afertilizer composition not having rice hulls stored for the same periodof time.
 7. The composition of claim 6, wherein the crystal aspect ratioof said fertilizer composition is reduced to a level in a range fromabout 30:1 to about 4:1.
 8. The composition of claim 1, wherein saidrice hulls are about 1-50% by weight of the granule.
 9. The compositionof claim 1, wherein said urea containing fertilizer has a urea toformaldehyde ratio of about 1.5:1 to about 8:1.
 10. The composition ofclaim 1, wherein the fertilizer composition has an average crystal areaof urea crystals of less than 60 μm² formed after 2, 3, 4, 5, 6, 7, or 8months.
 11. The composition of claim 1, wherein said compositioncomprises less than 20% water by weight of the composition.
 12. Thecomposition of claim 1, wherein said granules are about 0.5-5 mm insize.
 13. The composition of claim 1, further comprising potassiumsulfate, ammonium sulfate, 3,6-Dichloro-2-methoxybenzoic acid (dicamba),2,4-dichlorophenoxy acetic acid (2,4-D), methyl chlorophenoxy propionicacid (MCPP-P), or mixtures thereof.
 14. The composition of claim 1,wherein said granule comprises 40-60% by weight urea containingfertilizer.
 15. The composition of claim 1, wherein said granulecomprises 10-25% by weight ground rice hulls.
 16. The composition ofclaim 13, wherein said granule comprises about 0.5-4% by weight2,4-dichlorophenoxy acetic acid (2,4-D), 0.5-1.5% by weight methylchlorophenoxy propionic acid (MCPP-P), 0.04-0.2% by weight3,6-Dichloro-2-methoxybenzoic acid (dicamba), or mixtures thereof. 17.The composition of claim 1, wherein said composition further comprisesfertilizer components selected from the group consisting of calciumnitrate, ammonium sulfate, sulfur-coated urea, isobutylidene diurea,ammonium nitrate, ureaform, urea formaldehyde reaction product, urea,anhydrous ammonia, ammonium polyphosphate, monoammonium phosphate,diammonium phosphate, potassium nitrate, potassium sulfate, polymercoated urea, micro elements, mono-ammonium phosphate, potassiumchloride, and mixtures thereof, herbicides, micronutrients,biostimulants, macronutrients, inert solid carriers, or mixturesthereof.
 18. The composition of claim 17, wherein said fertilizercomponents are calcium nitrate, ammonium sulfate, sulfur-coated urea,isobutylidene dirurea, ammonium nitrate, ureaform, urea formaldehydereaction product, urea, anhydrous ammonia, ammonium polyphophate,monoammonium phosphate, diammonium phosphate, potassium nitrate,potassium sulfate, polymer coated urea, micro elements, mono-ammoniumphosphate, potassium chloride, or mixtures thereof.
 19. The compositionof claim 1, wherein said composition has an average odor concentrationof less than 550 o.u./m³.
 20. A fertilizer composition comprisinggranules comprising rice hulls and a urea containing fertilizer, whereinthe urea containing fertilizer is coated directly on an outer surface ofthe rice hulls, adhered directly on the outer surface of the rice hulls,or impregnated into the rice hulls, wherein the rice hulls are sprayedor soaked in the urea containing fertilizer.